An idea · Classical Greek · first attested 375 BCE
The Allegory of the Cave
We mistake shadows for the real world.
In Republic VII, Plato describes prisoners chained from birth in a cave, watching shadows on the wall, certain that the shadows are reality. One prisoner escapes, painfully ascends to sunlight, sees the real world, and returns to tell the others – who, predictably, want to kill him. The image is a theory of knowledge and a political theory at once; it is also Socrates' fate, written in advance.